Suspicious PowerShell Download

Severity: medium
Author: Florian Roth (Nextron Systems)
Source: upstream

Detects suspicious PowerShell download command

MITRE ATT&CK coverage

Tactic	Techniques
Execution	`T1059.001` Command and Scripting Interpreter: PowerShell

Event coverage

Provider	Event ID	Title
PowerShell	400

Stages and Predicates

Stage 1: `all of selection_webclient`

Data|contains: Net.WebClient

Stage 2: `all of selection_download`

or:
Data|contains: '.DownloadFile('
Data|contains: '.DownloadString('

Indicators

Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.

Field	Kind	Values
`Data`	match	`.DownloadFile(` `.DownloadString(` `Net.WebClient`